I won't be opening a Gmail account but not for any privacy reasons. I just don't need all that space. I once worked out how many average e-mails could be stored with average file attachments. The number involved enough zero's to give me a headache. It doesn't take much to that

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Work things out using the right-hand column of
this calculator if you like. Use your own figures maybe but I think the average HTML e-mail (as opposed to plain text that takes up alot less) is about 15 or less Kilobytes. Not all e-mails have file attachments but just suppose they did. What's an average file attachment? Images are probably the largest sort, so maybe 2 - 300 Kilobytes? (less than that is better for e-mailing purposes). Type 300 into the Kilobytes box on the calculator, hit the 'Calculate' button and see how much of a Gigabyte it uses.
Even if Gmail is used purely for storage of images, only a fraction of the Gigabyte will be needed. Try the calculator on a 500Kb or even a megabyte image (images become very slow to upload after that). It's no wonder nothing ever needs deleting from Gmail. I can't think what good all that space is. It's a bit like having a cake that's the size of a football field. Very nice but not a hope of eating it all.
The privacy part wouldn't worry me. I long ago realised there is little privacy on the Internet. I'm sure my IP address (being a more or less static one) can be tracked for advertising purposes. Also, if I were up to no good on the Internet, I could be traced to my ISP ...and further if the authorities thought it necessary.
If I did have a Gmail account and e-mail information was scrutinised, what would they find out? That I'm going out mountain-biking, or that I had a good time at my birthday party? I don't mind anyone knowing the sort of information my e-mails hold. Maybe on those two subjects Google would target me with ads relevant to cycling and keep-fit products. They'll realise I need alot of puff to blow out the number of candles my cakes have these days
However, If I was into any illegal activities, or if there was anything I wanted to keep strictly confidential, I wouldn't communicate by Gmail anyway, or any other Internet method without some sort of strong encryption. Even then, nothing's 'un-crackable' I suppose.
P.S. Sorry for the bits mentioning 'cake'. I've just been eating some, so it's foremost in the mind at present.