Most of us will be aware that Google only uses the first hypertext link on a page as a signal. Does this include menus?
Let's see if I can explain...
For example lets say your website is about mauve widgets and your common menu has a homepage link, "Home" at the top of the page. If you link to the homepage using the anchor text "mauve widgets" within the text content on another page will this be ignored? (Since there is already a text link to this page on the menu above.)