There's a lot you can buy that claims to accelerate your Web applications, improve equipment and bandwidth utilisation, and boost the end-user experience but many Web server front-end products are simply beyond the budget. The good news is that you can add many of the same speed-enhancing techniques directly to your Web servers - and cheaply too.
HTTP compression can be added to most Web servers quite inexpensively, or for free. In the case of Apache, mod_gzip or mod_deflate - open source tools you can readily find on the Web - are common solutions.
For Microsoft servers running IIS-6, compression is a native feature and requires a simple configuration change to enable basic features, although detailed configuration can be troublesome without using specialised utilities or registry editing. There is also a thriving market for third-party HTTP compression filters for IIS including httpZip from Port80 Software and TurboIIS.
Do understand that when using compression you should see an increased CPU load on your server but Web servers typically have plenty of cycles to spare because they are network- or disk-bound.
Interestingly, when we tested specialist Web acceleration boxes against IIS-6 native compression, the latter turned out to offer more compression in many cases. For example, in one test with default settings IIS-6 compression reduced 500k to 137k, with the next best result being 162k. While tuning should bring an appliance closer to the IIS result, given that all approaches use the same technology at their heart, that result certainly would surprise most observers.
To help offload servers you may consider setting up a reverse proxy. This is often done using on open source program called Squid. Windows environments often choose Microsoft's ISA Server instead, but consider that your proxy cache doesn't necessarily need to be the same technology as your origin server.
If you have load problems because of specialised content such as multimedia or SSL traffic you could simply segment your load using DNS. For example, images.sitename.com and store.sitename.com might be dedicated solely to do specialised work such as deliver images or perform encrypted e-commerce transactions, and have simple link changes balance traffic directly. Making hardware modifications such as adding in a relatively inexpensive SSL coprocessor card such as HP's AXL300 might also be in order for a specialised server.
No hardware or software is required for one of the most important efforts you can make to improve the delivery of a Web site - informing your Web designers and developers that delivery does indeed matter. Un-optimised Web pages can cost an organisation much more in hardware and bandwidth than you might guess.