One of my pet projects is BioStor, which has been running since 2009 (gulp). BioStor extracts articles from the Biodiversity Heritage Library (details here: http://dx.doi.org/10.1186/1471-2105-12-187), and currently has over 110,000 articles, all open access. The site itself is showing its age, both in terms of performance and design, so I've wanted to update it for a while now.