they dont have to be mates to like your page,you want randoms. its not like your personal page where you have friends and what not and invite people or they invite you. no
you have "likes" instead and people just click like.
how many friends that person that clicked like on your page has just appeared on all those peoples pages, for example- one person likes your page who has 100 friends then there is a possibility 100 people have just seen that person has liked your page, that is good advertising.
and mate it does put bums on seats. mate i post something new on facebook the next day i have a tonne of people coming in asking for it. best advertising ever. and the more clever you are with your page the better the result. this is no different for paying for an add on tv or in the paper for advertising,its still advertising. however this way its more interactive. also remember people use facebook like google, eg they want to come to Our town for a day trip they search Landsborough it will comes up with all these businesses at landsborough. if they visit the store and they click "check in" at our store, then again all there friends see that person is at landsborough at our shop. and being a cafe people are sitting there using their phone and good chances of adding your shop if they like it. make sure you advertise the fact you have a facebook page and a webpage. best part about it, its free.
people hate facebook as mentioned but they are minority, even though those who hate facebook have a very valid points as to wh ythey hate it, its crazy not to use it for your buisness, as many of the reason they hate it is the reason it works for buisness. but you do cater for the none facebook users in other ways like webpages phone book and all that, but you always run fascebook with those forms of advertising also, and mantion you have it so fans of your shop will help promote it, its just like word of mouth however it can reach more people. also the page gives you feedback like weekly views and howmany people your page has reached. so always post in prime time, so it has a better chance of reaching more people. thats a good trick also