If someone online gets your hackles up, try responding as you would if they were sitting next to you. The temptation to respond more strongly must be resisted. When meeting people electronically, good manners are more, not less, important. This is due to the authority which computers seem to lend to the data they process. All information from any source should be carefully scrutinized for its accuracy before any reliance is placed on it.
Computerized information is no exception.
As with any genealogical resource which has been derived from original source material, computerized information should be used as a road sign pointing back to the original source records. When an entry is found in a database such as the International Genealogical Index or in one of the commercially available CD-ROM databases, the entry can only be used as a helpful clue. The information from the entry must be further verified by consulting the original record. Genealogical information without proper citations is only hearsay. We've all learned the value of citing our sources of genealogical research.