Short version: I want to look professional even in the situations where I'm unable to help other teams in the office. I don't care about creating shallow impression of being more skilled than I actually am but I also don't want to downplay my actual skills by exposing my lack of knowledge on topics which are not strictly part of my job. How can I achieve that in the given situation?
Longer version: Around 5 months ago I got my first job in IT sector as a webmaster in a small company. Initially there was another coworker with the same position who had over 4 years of experience in the company, and even more years outside of it, who has left for another job around 2 months ago. As far as I got to know him I got an impression that he could solve almost any problem anyone in the office ever had, and if he couldn't help he had exact knowledge of why he can't do that and what else should be done.
Now I am the only webmaster and I have big shoes to fill as I don't have nearly as much experience and knowledge as he did. My boss said that he knows I probably won't be able to do the work as efficiently as he did and told me not to worry about it. Also my contract has exactly listed things that are part of my job, and I know that the previous webmaster was going far out of what he was required to help others.
Now the thing is that we also have a SEO (Search Engine Optimisation) team, and the leader of that team often relied on the coworker whom I am now replacing. So the SEO team leader sometimes asks me an in-depth questions on SEO/SEM (Search Engine Marketing) topics, on which I have limited knowledge.
I'd like to learn more about it and I do every day but honestly I don't care about it that much to spend my free time digging into inner workings of it rather than just coding my personal projects. Also it is not in my contract to handle SEO tools and analyse their data, but as a webmaster it is important for me to have at least general knowledge on the topic. Also, if I could I would like to help the SEO team especially when I don't have a lot of work but sometimes I'm just not capable.
Now I probably am sensitive on this topic because at the begining of the job I had few "f*ck ups" and don't want to make impression that I am incapable of helping the other team as previous coworker did. I know that except for that I usually do my job well and I'm actually hoping to get a raise in the near future (I've been talking about it with my boss and he was affirmative that could happen if I do my job right) and the SEO team leader might have a big impact on judging my skills even though I'm in another team. So now I don't want to undermine my image by saying I don't know something most of times when I'm asked for help. It was never a problem that I was unable to help but I know the impression persists.
The company I work for is very small (less than 10 people) so it is usually clearly visible to boss how helpful to others I am.