Google Web Elements make it very easy to add several Google services to a site by adding some embed code.

Note: Check out the terms of use for each.
eg. terms of use for Google site search seem to prohibit its use on a business directory.

http://www.maximumpc.com/article/features/blue_screen_survival_guide
via Lifehacker

How many emails do spammers have to send to get a sale?
Here's a resourceful attempt to find out...
http://www.icir.org/christian/spamalytics/

Spam conversion rates
Various figures are quoted for this ( 0.00001% , 0.00036% etc), but it will vary depending on the thing being sold. Safe to say it's "a lot"! The kind of numbers you would need to send to make it worthwhile are likely to get you outed as a spammer, so if you fancy going for it anyway you may need "Online Reputation Management" services.

Conficker Eye Chart

via Lifehacker

Adobe Reader is forever being targetted by the bad guys, and Adobe aren't always too quick to respond to new threats. This is why many savvy users are switching to alternative PDF readers.

See http://www.pdfreaders.org/ for suggestions.
Not included here is Foxit, which fails the site's rules on transparancy and privacy.

http://blog.wfmu.org/freeform/2009/02/facebooks-25-things-about-me-all-my-internet-and-bank-passwords-and-pin-numbers.html

Make certain programs wait before running when you start your PC with this

via LifeHacker

Tiny Geocoder is very easy to use and has an API.
Multiplottr allows you to make custom Google maps with multiple flags. You can then embed these maps in your website.
Batchgeocode does what it says.

This one works for up to 24 hours.
Meltmail

http://www.fontsquirrel.com/

Big collection of supposedly free fonts for commercial use. Check the licenses!