Well, it is for its size!
When your web site is shown on someone's browser, a favicon is the tiny logo that sometimes appears next to it.
FAVICON stands for FAVorites ICON. At one time a favicon only appeared in a Favorites bookmark list. Of course your favicon could only go on parade if somebody bookmarked your site. Even then favicons were remarkably shy, sometimes disappearing for no apparent reason.
Favicons are now more robust. Depending on your browser, you may find a few in your History list and on your browser tabs. Favicon is no longer dependent upon somebody bookmarking your site.
These tiny icons can actually be pretty useful in quickly spotting a site in a list to revisit it. Many sites don't bother with a favicon and just display the standard browser icon. Their loss!
A favicon is in effect a miniature marketing logo - knee high to a shirt button, but it does get noticed.
Favicons now not only appear in more places. You can make your own favicon in different forms. At one time your graphic had to be an .ICO icon file. These days it can for example be a .GIF or a .PNG.
There are advantages to having an .ICO favicon. Fancy .ICO files can hold several images at different sizes and colour depths. If you want to go to town on one of these, there are specialised icon making apps.
For a perfectly serviceable favicon, it isn't difficult to make your own .GIF or .PNG favicon in a desktop art app like Photoshop or Elements.
Finding out if your favicon is on parade can be difficult because you can't do too much testing to find what makes this midget Pimpernel appear and disappear. You may only have your own computer to try it on.
Never mind. If your marketing logo is distinctive enough, even if it disappears it has probably done its work. We learn to recognise images faster than words. A really striking favicon will not be forgotten.
Good luck! ...