Wireshark is an open source network sniffing utility to analyze network traffic.

Mouseflow is a session replay / recording and website heatmap tool.

Wappalyzer is a cross-platform utility that uncovers the technologies used on websites.

Clicky Web Analytics is simply the best way to monitor, analyze, and react to your blog or web site's traffic in real time.

RidNacs is a free and very fast disk space usage analyzer for Windows.

Hiren's BootCD (HBCD) is a bootable CD containing a number of diagnostic programs such as partitioning agents, system performance

Inspectlet records videos of your visitors as they use your site, allowing you to see everything they do.

Charles is an HTTP proxy / HTTP monitor / Reverse Proxy that enables a developer to view all of the HTTP and SSL / HTTPS traffic.

TweakNow PowerPack is a suite of PC registry cleaner utilities that let you tweak every aspect of your Windows 7, Vista or XP operating system and browser.