The below widgets are about chat, IM, social bookmarking and much more. Maybe it is quiet simple, but it is going to make your blog a bit sticky.
Google Talk – Give visitors the ability to talk to you via Google Talk directly from your blog sidebar.
Jaxtr – Create a widget that allows people to call you on the phone without revealing the phone number to them.
Meebo Me – Meebo Me will allow you to create a chat box that you can install on your Blogger page, giving you the chance to converse with visitors to your site.
Skype – The official Skype widget allows you to create various buttons that can show your current status and also allows people to just click it and give you a call.
Tag-Board – Allows you to add a real-time chat board to your blog that your visitors and you can use to converse.
Delicious Linkrolls – Share your Delicious bookmarks with the world with this easy to install linkroll widget.
FriendFeed Widget – Share all of your FriendFeed activity with the readers of your site.
Google Friend Connect – A makeshift social network that runs across any site that has installed Google Friend Connect. You can join a site, see the other members, play games and more.
LinkedInABox – LinkedInABox retrieves your LinkedIn profile to display on your blog, allowing people to look through things such as your specialties and experience.
MyBlogLog – If someone visits your blog that is also a member of MyBlogLog, their avatar and username will appear in the box. You can then click on any person to check out their profile on the service.
Twitter – Add your Twitter stream to your blog and display anywhere from your last tweet to the last twenty. Also gives a link for people to be able to follow you.
Share on Facebook – A simple widget that allows your readers to share items from your blog onFacebook.
SocialFeed – A miniature lifestreaming widget that broadcasts your activities on sites such as Twitter,StumbleUpon, Last.fm and so on. Has several different skins you can choose from.
Add This – The popular social bookmarking button is available for Blogger accounts.
Easy Comments – This widget allows you to add commenting to any page of your site by placing the widget at the bottom of a page. Allows people to say if they liked the comment, includes comment threading and more.
Google Search – Add an AJAX powered Google search box to your blog that you can allow to search the web and your blog, or even just restrict it to the contents of your site.
Popular Posts – This widget will take a look at your comments, up to the last 5,000, and generate a list of which posts had the most conversation around them.
Recent Comments – Display the most recent comments on your blog in this widget so that readers can join in the conversation.
Related Posts – Not so much a widget as a hack, this will give you the related post functionality that so many WordPress powered blogs use.
ShareThis – The highly customizable green button that ShareThis is known for can be added to your blog. Choose if you want it for social bookmarking, users emailing your posts and more.
Shout List Icons – Be the king (or queen) of social sharing with this widget that generates icons for over 30 social sites your blog can be added to.
Tag/Label Cloud – Gives you the ability to install a traditional tag cloud in your sidebar so people can see what you write about the most.
Flickr – You can generate an HTML or Flash based badge of your photo stream to share your images with your visitors.
Mashable – Yes, now you too can share the best web-related news on your blog with the Mashable widget.
Picasa Albums – Display your public Picasa albums in your blog sidebar with this handy widget.