Simply put an email spam filter is a program that is used in the detection of unsolicited and unwanted emails which helps to prevent those messages from getting into a user’s inbox. Like many other types of filtering programs and email spam filter looks for specific criteria for its trigger. As an example these filters can be set to look for things such as their being particular words or phrases in the subject line of a message which it will then push away from the user’s inbox, often times into the spam folder. In reality this is one of the less effective means of filtering spam and often time’s legitimate messages will be filtered out while spam can make its way through to a user’s inbox.
There are more sophisticated programs out there such as heuristic filters which attempt to identify specific keywords or phrases that seem suspicious and then omit them. This is a rather simple means of helping individuals clean up their inbox to help alleviate the amount of time needed to properly and effectively read through their emails. This is something I highly recommend and it is something that I always make sure is offered by a web hosting company before purchasing one of their packages.