As I said earlier in this series, in this post,
In short, think of a source and citation as a journey and destination. The destination is the source, whereas the citation is how you got there and how you and others might get there again.
A citation is exactly where you found a particular reference, and in the case of websites when the website was accessed. Essentially, it is confirming a factual statement by backing it up with evidence. The reference will enable you and others to follow your research road map.
Some twenty five years ago I came across a file of Bastardy Bond Papers sitting in a local heritage room in a Surrey (England) library. I occupied about two months by transcribing the material. When the Surrey History Centre in Woking was opened, about five years later, it amalgamated the research materials from the Surrey Records Office at Kingston, A wonderful resource called the Muniment Room at Guildford and the local studies library which had been located at the central library in Guildford.
All the materials from those repositories retained their original reference information, the citations. Fast forward another decade and I wanted to use the Bastardy Bond material in an article and went to check the reference material, so I began by asking where the papers were? They had been deposited at the Surrey History Centre it was believed, but none of the staff at that time could confirm it as they had not been working there at the time. The Surrey History Centre eventually confirmed it, but the reference material had been changed.
Meanwhile, I record the citation of where the material is now and I also note the previous location of the material, because others, like me may well have used that material whilst it had been in the original location. To me it adds to the providence of the information and the documentation’s journey.