For Australian taxpayers we are taxed on our gross dividend...

For Australian taxpayers we are taxed on our gross dividend income which is the cash component plus the attached imputation credits - how much tax you pay on this depends on your individual marginal rate or your entity type (companies pay 30% but only 25% if they qualify for base rate entity concessions, super funds pay 15% but go down to 0% if they are full pension funds).
Once you have worked out your tax liability on your gross income you get a credit for the imputation credits, if your tax liability is more than the imputation credits you have to pay the ATO the difference, if your tax liability is less than the imputation credits the ATO give you a refund. Think of it like wages, you may be on a gross wage of $100k but your employer only pays you $80k in cash & sends $20k to the ATO. At the end of the year you still work out your tax on the $100k and the difference between that & the $20K your employer sends to the ATO is either payable by you or refundable to you dependent on your effective marginal rate - dividend imputation works on the same basis.
The reason why the term gross income is used by brokers, etc. is so you are comparing returns on the same basis. If you have $100 invested in a term deposit at 5% you get $5 interest which is straight forward. If you get fully franked dividends of $5 on a $100 share it looks on the face of it also to provide a 5% income yield but that is not the case. You are getting a gross income yield of 7.14% as you have effectively had tax withheld from your income. If your tax rate is 30% you will have to pay the ATO $1.50 of the $5 interest you received leaving you with $3.50 or 3.5% after tax. With the dividend you owe the ATO $2.14 of the $7.14 gross dividend income but this has already been paid in the form of imputation credits so you are square with the ATO & get to keep all of the $5 cash dividend you received meaning you get a 5% after tax yield.
Hope the above makes sense