Like are: Hotel and Hotels different, when i am bidding for these keywords? Would bidding on Hotel mean that the Google will consider both my keywords (Hotel and Hotels) here and would display the ad whenever any user types in any one of the two keywords?
Or do i need to mention both of these keywords separately.
I have also heard that the nouns which have simpler plural forms like book(s), Pen(s), Hotel(s) are alright. But when it comes to complex ones like Shelves (Plural of Shelf), Knives (Plural of Knife), Qualities (Plural of Quality), We MUST mention those keywords as individual ones.
Any help on this would be much appreciated.
Or do i need to mention both of these keywords separately.
For Yahoo, you don't - but, for Google, you must list variations such as plurals as separate keywords.
I have also heard that the nouns which have simpler plural forms like book(s), Pen(s), Hotel(s) are alright.
No, nouns aren't treated any differently... each singular / plural example you listed would need two unique keywords.