You are going to be sorry you asked... (I'm having to split this into multiple comments, as the comment field appears to have a 2500 character limit)...
You bet. And yes, it is confusing. I still don't have it all straight in my mind. I actually had some brief correspondence with ImgFlip via email, on the tags topic. I'm still waiting for some clarification. Part of the confusion is that the word “meme” is used on the site in two distinct ways – in one sense, to refer to a meme template, and in a second sense, to refer to an actual meme creation (the output of a meme template). This is further complicated by the fact that, in addition to “creations,” we also have “submissions” and “featured submissions.” If a creation is a meme, then these will also be memes. However, a creation need not be a meme (e.g. it could be a pie chart instead).
In any case, the only search functionality that I know of is the “meme search” (it's in two different locations, but appears to be the same search). To be clear, this functionality searches on meme templates, rather than meme submissions. The results of a search are broken down into "featured memes" and “user templates.” If you select a “featured meme” (or, less ambiguously, a featured/site template) you get a list of featured submissions that were created using that template. Selecting a “user template” will take you to a page where you can “Caption this Meme,” or return to “All Meme Templates.” If you choose to caption the meme, you are taken to the meme-maker. This page will also include a list of featured memes (or, less ambiguously, featured meme submissions) based on the template, if there are any.