First of all, this is an awesome plugin and I love using it. But here are my major concerns with this plugin which needs your immediate attention.
We all know how important is pageload speed for Google. I added Sharethis Plugin to my upcoming blog (under construction) and I find that page load speed is affected. I checked the Sharethis support article which speaks about Asynchronous loading but it does not add much value. I used caching plugin, tried different methods available on your website. But it does not seems to be really helping. I also find a third party link http://b.scorecardresearch.com is added to my page.
Here is the output:
Avoid a character set in the meta tag
The following resources have a character set specified in a meta tag. Specifying a character set in a meta tag disables the lookahead downloader in IE8. To improve resource download parallelization, move the character set to the HTTP Content-Type response header.
The following resources are loaded synchronously. Load them asynchronously to reduce blocking of page rendering.
Specify a cache validator
The following resources are missing a cache validator. Resources that do not specify a cache validator cannot be refreshed efficiently. Specify a Last-Modified or ETag header to enable cache validation for the following resources:
Specify a character set early
The following resources have no character set specified in their HTTP headers. Specifying a character set in HTTP headers can speed up browser rendering.
Remove the following redirect chain if possible:
Minifying the following HTML resources could reduce their size by 673B (3% reduction).
http://edge.sharethis.com/share4x/index.d1a3b7c6e75e9a29fa90faf3a7402731.html could save 423B (14% reduction) after compression.
Request you to go through and optimize the plugin in such a way that it wont affect page load. Options like Asynchromous loading, optimizing codes, moving codes to footer would be helpful.
Could you please let us know how to improve page speed when used with this plugin.
Appreciate your efforts