Say you are doing a paper or project on TV usage and you are looking to find out how many people watch TV. Looking for online surveys is probably your best bet to quickly retrieve data. However, don't just take this data at face value. There could be factors that could make this survey totally useless.
Since techno-revolutions happen over night, data fields like dates and times might be obsolete, especially when it comes to technology like television set models, stereo equipment or cellphones.