there are two general methods for calibrating the molecular clock using fossil data: node calibration and tip calibration.
For example, a google search for "the green goldfish", with quotes, currently initially reports around 22,700 results, yet on paging through to the last search results page shows the returned number of hits to be 370.
Which example describes a method of relative dating openstudy
Calibration, also referred to as tip dating, is a method of molecular clock calibration in which fossils are treated as taxa and placed on the tips of the tree.
 an arabic name, for instance, needs to be searched for in the original script, which is easily done with google (provided one knows what to search for), but problems may arise if for example english, french and german webpages transcribe the name using different conventions.
Which is an example of a relative dating method
Legends are often reported widely, for example hundreds of sites report that the uss constitution set sail in 1779, although the correct date is 1797.
This method does not rely on the interpretation of negative evidence to infer maximum clade ages.
This understanding is based on fossilized bones and skulls that have been uncovered in east africa and dated accurately by radiometric dating.
^ for example, if there are 16 hits at google books under one name, and 24 under another, there is only a 70% confidence that the second name is actually more common.
For example, there may be many references to acupuncture and confirming that people are often allergic to animal fur, but it may only be with careful research that it is revealed there are medical peer-reviewed assessments of the former, and that people are usually not allergic to fur, but to the sticky skin particles ("dander") within the fur.
Google trends can compare usage in the "news" category ("tidal wave" vs "tsunami" example), but this may not be reliable for older news.
Methods can provide more appropriate estimates of divergence times, especially if large datasetssuch as those yielded by phylogenomicsare employed.
Carbon-14 atoms would not work for dates that go as far back as early hominines; instead, potassium found in the volcanic ash was used in a potassium-argon radiometric-dating technique.
Selection bias for example, an arabic speaker searching for information on homosexuality in arabic, will likely find pages which reflect a different bias than an english speaker searching in english on the same subject, since popular and media views and beliefs about homosexuality can differ widely between english speaking countries (usa, uk, australasia) that tend to include a higher proportion of homosexuality-accepting groups, and arabic speaking countries (middle east) that tend to include a lower proportion.
Stratigraphy is one clue used by archaeologists to determine the relative age of an artifact or site.