Main SEO problems that vshare have from: http://www.seositecheckup.com/

HTML Compression Status
Should compress your HTML to reduce your page size and page loading times - this will help your site retain visitors and increase page views. Commonly used methods for compressing html include GZIP and ob_gzhandler http://us2.php.net/ob_gzhandler. If you were using compression, you could be compressing your HTML size by 77% to further reduce page loading time. If you were using compression, you could be compressing your HTML size to 4.48

x-cache Header
It does not appear that you are caching your pages. Cached pages serve up static html and avoid potentially time consuming queries to your database. It also helps lower server load by up to 80%. Caching most visibly benefits high traffic pages that access a database, but whose content does not change on every page view. Common caching methods include Alternative PHP Cache, Quickcache, and jpcache. Caching mechanisms also typically compress HTML, further reducing page size and load time.

Images Expires Tags
Your site is not using expires headers for your images. An expires tag can help speed up the serving of your webpages for users that regularly visit your site and see the same images. Learn more about how to add expires headers to your images. http://jeremy.zawodny.com/blog/archives/009272.html