Sometimes when you are attempting to solve a level, you will find a word, phrase, etc. that isn't the actual solution, but is related to it. Let us say that the current level is (invalid - just an example):
Let us also say that you believe that the solution to this level is something to do with the phrase "let's go". In these cases, it may be useful to attempt to navigate to that page anyway (but remember, there are no spaces or special characters in the URL):
If you are lucky, and on the right track, there may be a page there with an additional hint, confirming your suspicions. This is what we call an egg page. However, if there is not, you will encounter an error page.
Note: You will never need to guess a solution for a level.