What is a word similar to "amateur" yet having a strong connotation of someone who likes something?

A possibly useful word for your case is hobbyist.

A hobbyist is someone who is interested or engaged with a field but specifically as a hobby and not a professional pursuit. It lacks the negative connotations of amateur, instead it has a casual implication.

Aficionado - usually used by people who are professionals as a compliment to someone who is an amateur but is well versed in the subject. I was once called a "lock aficionado" by a locksmith, and a "stats aficionado" by a statistician. Sven mentioned it in a comment, and I think really this is the correct answer.

Dilettante - Another option, and can be used either positively or negatively depending on the context, but unlike aficionado the subject is rarely prefixed. For example, in an art gallery - "You seem to know a lot about Monet - do you paint yourself?" "Oh no, i'm just a Dilettante!". Or "I really like astrophysics, even though I don't own a telescope. I suppose you could call me a dilettante." In the harder sciences this can be used mockingly though.

One word that is coming into more common use lately is Follower

1. someone who supports and is guided by another person or by a group, religion, etc.

2. a person who likes and admires (someone or something) very much

3. someone who does what other people say to do

The second meaning is what you're looking for - it carries the connotation of actively being a member of that group, but not being a particularly skilled member. It doesn't necessarily mean professional (in fact, usually it means they aren't professionally involved) but it does carry the meaning that one is very interested in the subject, but not experienced in it.

aspiring would be great in this context, referring to one who hopes to achieve some position or skill. The word connotes someone who would have "amateur" abilities in a given topic.

from aspire

Aspire verb (used without object), aspired, aspiring.

1. to long, aim, or seek ambitiously; be eagerly desirous, especially for something great or of high value (usually followed by to, after, or an infinitive)
   [Dictionary.com]

As an adjective:

Her 18-year-old daughter, an aspiring animator, is headed for art school, she says.

Newcomer might do the trick. Its definition isn't exactly what you're looking for, but in an informal/somewhat conversational answer on SO, I think your point would be communicated as you intend.

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EDIT

Example: For newcomers to this topic, you might enjoy reading this article I found. To me, "newcomer" implies that there people who are new to the topic but are interesting in learning more. Typically, if someone is interested in learning about something and seeking out information on their own volition, and they are new to the subject, they also typically like that subject. This is an informal use of the word and relies on its connotative aspects, but in no way would I ever interpret the word as meaning: "For people who would like to learn more, but actively dislike the subject" – if fact, as I've attempted to state, I would infer the exact opposite.

I thought of connoisseur. It indicates advanced knowledge, and one must deduce that great liking preceded the exacting study needed to become a connoisseur. And it avoids the potential negative of "amateur."

For completeness, I feel compelled to point out that in some contexts, amateur still carries the traditional ("love-based") meaning. Merriam-Webster gives the following definitions for amateur:

1 : devotee, admirer
2 : one who engages in a pursuit, study, science, or sport as a pastime rather than as a profession
3 : one lacking in experience and competence in an art or science

Most notably, amateur sports are sports whose participants are not paid, but who play "for the love of the game". Moreover, these participants can be any skill level, from beginner to world-class.

For example, it may be slightly antiquated, but there is still a large number of people who refer to the Olympics as the pinnacle of amateur sport. Obviously Olympic athletes compete at an extremely high level, equal to or very near professional.

Music is another area where amateur, depending on who is using the term and in what circumstance, could mean something like the Olympic sense (actually, very much like J.J's description of aficionado); or it could be used in a derogatory way when referring to an actual professional musician who isn't very good.

The term rank amateur, on the other hand, refers to a complete beginner or someone with low skill level. (And typically does not even imply any particular love of the endeavor.)

However, I acknowledge that amateur in common usage tends to connote unskillfulness or casualness or both, and thus usually is roughly equivalent to hobbyist. The single word that best captures the spirit of amateur in the Olympic sense is probably enthusiast.

I like the word "Novice" here. It describes a user with lack of experience , but has an undertone of a interest.

Student has the connotation of being an amateur, while still retaining a taste or desire for that subject (at least in some cases; perhaps not for those described by the first definition below):

1. a person formally engaged in learning, especially one enrolled in a school or college; pupil

2. any person who studies, investigates, or examines thoughtfully

Avid invokes the passion amator seems to retain, but is an adjective meaning:

1. showing great enthusiasm for or interest in

Combining the two in the SO example, you could indicate the answer is "For avid students...."

Your example with the wine also seems to indicate an adjective rather than a noun. Avid certainly won't work. Even a word like Enthusiastic seems somewhat contrived.

Interested is somewhat generic:

1. having an interest in something; concerned

Further defining Interest gets us closer:

1. the feeling of a person whose attention, concern, or curiosity is particularly engaged by something

But it conveys the right meaning if someone holding a bottle of wine asked, "Who is interested?" No professional certifications implied, nor connotations of ineptitude, even if it's not quite as passionate as amator seems to be. It also doesn't quite convey the familiarity with the subject, as interested could mean interested in getting drunk as opposed to having knowledge of and being interested in savoring and enjoying the flavor of the wine.

Avocation has the right connotation with more passion implied than interested, but I can't figure out how you'd use it in the context.

1. something a person does in addition to a principal occupation, especially for pleasure; hobby

FWIW, in the context of the SO question referenced, I don't feel Novice, Newcomer or the like really fit the bill, as the question is quite scholarly, and would require someone pursuing the answer to have some significant existing knowledge of the subject. In the context, "For aspiring students" comes close, but may have an arrogant connotation of "keep working on it; you're not where I am yet" rather than the more generic avid or interested.

I did like the more-than-one-word answer you gave: "For people who want to figure this out...."

buff

a devotee or well-informed student of some activity or subject

Example: He's a real history buff.

Anorak - descended from the warm but unfashionable outerwear worn by trainspotters (a group deeply interested in specific trivia, the details of railway engines and their numbers and routes)

In British slang an anorak /ˈænəræk/ is "a person who has a very strong interest, perhaps obsessive, in niche subjects."

It takes little skill or ability to note numbers, so minimal ability is required, and the person must have the patience and stoicism to stand on a possibly cold and wet railway platform for hours waiting for a train, in order to note its serial.

This answer falls down on the like component. An anorak doesn't have to like what they're doing, and instead the ability to persevere despite the conditions and dislike could be a polarising feature of an anorak.