At a recent conference talk (sorry, I forget which one), there was a quick example of poor web performance in the form of a third-party widget. The example showed a site that installed the widget in order to add a "email us" button fixed to the bottom right of the viewport. Not even a live-chat widget — just an email thing. It weighed in at something like 470KB, which is straight bananas.
Just in case you are someone who feels trapped into using a ten-ton widget because you aren't yet sure how to replicate the same functionality, I've prepared a small chunk of HTML for you.
It's 602 Bytes, or about 1/10th of 1% of the size of that other widget — with nothing to download, parse or render block.
Perhaps on your own site, you'd move the styles out to your stylesheet and add in some hover and focus styles.
My friend Richard showed me a new product he built called Surfacer. It's like an RSS widget that you can put anywhere.