I second the non-compliant code issue - a full HTML document markup + doctype declaration is included in the code for the plug-in.

The english-language version still includes many german-language social bookmarking sites, even where english-language versions exist (you can disable these though of course).

You have to hack the plug-in configuration to add the module class suffix field, which is a nightmare for non-technical users who use stock templates (which base module styles on this field).

Overall it's a good basis for a starter in plug-in development to improve on, but I wouldn't advise using this version on a production site.

I tested this plugin for quite a while and it was quite useful. Unfortunately i found out, this plugin does create invalid (X)HTML-Code.
I will surely check this one out again, if this problem is solved in a future version of this plugin.