While many years ago I started to collect weblinks for the information I was finding, it did not take long to realize it was a useless pursuit. Yes those links you collect may be valid for a couple of months or if you are lucky a couple of years.
But I have found that after over 10 years of research all of those links are changed or abandon. It is better to keep accurate records of where you found the information. When you need to review the online source it is easy to Google it IF it is still online.