At Yahoo, it takes two, baby, to make a website so real. In the process of acquiring new websites and revamping old ones, Yahoo's accumulating a curious set of twins. On Monday it upgraded the year-old My Web service -- a relaunch that overlaps with the recently acquired online-bookmarking service Del.icio.us -- and this morning it released a Flickr-inspired version of Yahoo Photos, the Web's largest photo sharing site.

Michael Arrington at TechCrunch approves of the new photo site, pointing out that it allows unlimited storage and "brings in the best of Flickr," the photo-sharing site Yahoo purchased last year. And therein lies the rub: Yahoo has chosen to to keep its home-built applications separate from its sexy new acquisitions like Flickr and Del.icio.us, leaving users unsure which application to use. Flickr and Yahoo Photos both let users share photos online, while Del.icio.us overlaps with My Web in providing a way for Net surfers to categorize and share Web bookmarks.)

"So I am a little confused," writes a TechCrunch reader. "Should I pay for Flickr's Pro service or do I use Yahoo Photos, which does exactly the same for free?" Commented another reader, "About Del.icio.us and Flickr, anyone know why Yahoo is trying so hard to sideline two of its best purchases?" Showing up on the TechCrunch message board, Flickr founder turned Yahoo executive Stewart Butterfield spun the situation as best he could: "Don't worry... Neither Del.icio.us nor Flickr are being sidelined. They are different, slightly-overlapping-but-complementary products."