For a long time, the 802.11b wireless standard was the only logical commercial option, both for business and home use. When compared to the A standard, B is incredibly unimpressive, and its success can only be attributed to its early and wide availability, and relatively low cost (both manufacturing and retail costs).
802.11b, unlike its older brother, uses the already flooded 2.4GHz band. It also only supports a maximum net speed of 11 Mbps. Realistically, does being on the 2.4GHz band really effect its performance? The answer to that question is a resounding yes. While some 802.11b users may go through life never experiencing problems, others (particularly those with cordless phones that operate on 2.4GHz) will experience nothing but problems. As a support specialist, I have received dozens of calls from wireless users losing their Internet connection every time they receive a phone call.
There are, of course, ways around this. In my own home I am using the 802.11g standard (discussed below, and which also operates on 2.4GHz band). Before installing my network I preemptively required my family members to do away with their 2.4GHz cordless phones, as these are also almost as widely available on 5GHz nowadays. Additionally, I placed my wireless router as far as possible from the microwave. With this configuration, I don't experience any problems with signal interference.