No source, no matter how authoritative it may seem, is free of error. On this web site, you will find numerous citations that will tell you where the data came from. These are important to note if you are serious about the integrity of the research you are doing for your family.
There are primary sources, such as census materials, birth certificates/records, and so on, that are public records and the best available data. Even these have errors, but are usually reliable. At the other end of the spectrum is data taken from secondary or tertiary sources.
Secondary sources are things like obituaries and compilations taken from primary sources. These have a higher rate of errors than primary sources due to handwriting interpretations, illegible originals, digit transpositions, and a variety of other induced errors. Whenever you use a secondary source, it usually will point you to a primary source to verify the data. For instance, an obituary will point you at the location of the death certificate, which is primary source information.
Tertiary sources are other peoples' research, and this varies in quality from the outstanding (where the individual has used primary sources and eliminated some of the errors found there, including rationale for this correction) to the unbelievably wrong. Do not believe any tertiary source (such as this web site). Always try to find a more reliable source. Good tertiary sources point you where better information may lie. On this web site, whenever information is based on reasoning, circumstantial evidence, and sometimes when the information simply looks suspicious, you will find notes in the text that "proof is required." Proof, in this case, means some primary source needs to be found, if possible, to verify the data.
With these caveats in mind - please enjoy the website, and don't believe anyone until you see the original yourself.