You may have noticed that I killed third party javascript widget thingies on my site (maybe not, maybe you read only via RSS). Verious money making schemes are gone (most didn't work, but that's no my focus here). I killed my site widgets because they were slow and made my site appear to be slow as well.
What?
What are Widgets (Blog Widgets)
Widgets are the little things that people place in the sidebars and other low-value parts of their site. They do this to provide additional features, to show affiliation with something, to prove the value of their blog, to make money from their blog, basically they do it for a lot of reasons. Prominent examples include the MyBlogLog widget, Last.Fm widget, Adsense widget, Flickr photostream widget, the Google Analytics widget (hidden widget, but still a widget).
Even fast blog widgets are slow
Browsers are designed to download files from webservers. It used to be that a page was a page. You downloaded that one file and you were done. Then we got images, and css, and javascript. So your browser downloaded 4 or 5 files. Typically this was done serially (one after the other) which means that the page loads first, then the css and javascript, and finally you see the images loading into the page one after the other. Some browsers can doanload in parallel where they grab multiple files at the same time which speeds the process because it takes full advantage of your network link.
Each file that gets downloaded takes time because of the size of the file itself and also because of the additional request. Each file request has additional overhead associated with it. So, downloading 1 file that is 2MB will take less time than 2 files that are 1MB each.
Widgets add more files to your page. More files makes your page slower, even if they are served quickly. But what if they are served slowly or - ghasp - the widget server goes down.