I highly doubt that your queries are primarily coming from your own engine. The results are too good. It has good ranking, spelling correction, super large indices, and is fast. For example searching "GTGACCTTGGGCAAGTTACTTAACCTCTCTGTGCCTCAGTTTCCTCATCTGTAAAATGGGGATAATA" works even though it only occurs on a few pages and as the blog post that string came from explains, you need super fancy indexing techniques to handle things like that quickly. You also talk about this as if it is a single-person project, which makes it even less likely you made all this from scratch.
I like the concept and the parts that you undoubtedly make yourself like the UI, image retrieval and caching, are really good. This is a great site don't get me wrong. I just think you should be more forthcoming about where your results are coming from.