Is your Apache Web server slowing down under the weight of streaming media content or database-driven applications? Lighttpd, sometimes pronounced "Lighty," is a lightweight HTTP server that can help alleviate Apache's load by serving static content or CGI scripts. Since Lighttpd uses fewer resources per request than Apache alone, it can generally serve most static content faster than Apache. It also benefits from an actively developed FastCGI interface that performs true load balancing, giving you all the performance benefits of compiled into Apache modules such as PHP.

Load, in computing, is a measure of the amount of processing a computer system is currently performing, usually in the form of a scalar and as some variation on a percentage. - Wikipedia definition.

Well, yes, basically the server load is a number. The number is usually under the x.xx format and can have values starting from 0.00. The number expresses how may processes are waiting in the queue to access the processor(s). Of course, this is calculated for a certain period of time and of course, the smaller the number, the better. A high number is often associated with a decrease in the performance of the server.