Why is tagging so important? Isn't it great to find what you are looking for! That's what tagging is all about, keywords, categories, you name it in order find your posts.
What is your favorite feature on Flickr? I like the Mappr feature in that you can focus on on a region and find photos that have been geographically linked. Creative Commons is also a neat feature for licensing your photos.
Check out the user groups... what is an online community? I guess if you have alot of time, you can really keep busy with Flickr, including signing up with various user groups and online chat communities where you can actually talk about your photos.