Hi zoider,
I agree with
@Paidiske that in many fellowships it's hard for a pastor not to know what is given in offerings. The only way to really give offerings anonymously is to put cash in the plate. Making offerings online or by check or with an app is always going to indicate 'who' is making the offering and where the money is coming from.
As far as a pastor mentioning someone's specific giving, I certainly wouldn't expect it to be by name in any sermon message or general fellowship announcement without clearing it with the giver first. However, to make a general claim that a specific offering was received, such as: "We received an offering of $2,000 for the upgrade to the PA system." I wouldn't find offensive in any way. That's anonymous and unless you know what everyone else is giving, it may or may not be your gift that is being referred to. However, in general, I think that while many pastors know what their individual congregants give, it shouldn't be offered in public conversation.
You however, aren't really specific about how the offering was mentioned. Was the pastor thanking you in a private conversation for your offering? That's ok in my book. I would respond, "I just hope that the fellowship will use it to the glory of God." BTW as someone mentioned earlier concerning taxes. Fellowships generally send out 'giving' statements to parishioners early on in the new year because they are tax deductible and most people that give, and can deduct such expenses will do so. If there were no accounting for the offerings made and by whom, that wouldn't be possible. So, I think your understanding that you thought offerings were anonymous, isn't likely true in any fellowship. However, 'who', among the fellowship knows can be different with different fellowships. For smaller more intimate fellowships, the pastor may be a part of the bookkeeping process. For larger fellowships, there are usually others who count and tally the offerings.
Anyway, if your pastor made some grand announcement during the message time that we sure want to thank so-and-so for giving $500 last week, I wouldn't approve. If he was merely mentioning your offering in a private discussion with you, I wouldn't be particularly offended unless he was insinuating that I was cheap and wasn't giving enough. But, bottom line, if you really desire that your offerings be anonymous, then always give cash. Just slip it in the plate or the collection coffer in the foyer or whatever and no one knows, unless they were watching you put it in, where the offering came from. That's generally what I do. I take a few hundred dollars with me on Sunday morning and fold up my offering and put it in the plate.
God bless,
Ted