Why the "Yo"?
The first things Spanish-learners learn are the subject pronouns.
Then you learn they are somewhat optional.
Then you learn (on this site) that they are downright forbidden! 
Then I walk into a Bank of America today... and all the signs are in English and in Spanish... remember, vivo en la Florida. 
I can help!
Yo puedo ayudar!
I can protect...
Yo puedo proteger...
Why are they using "Yo"?
12 Answers
We almost exclusively use the subject pronoun to say:
I, unlike others, are going to do this or that....
Mañana voy al cine.
Pues YO no voy!!!
I am going to the cinema tomorrow.
Well, I am not going.
So, they are doing the same here, they can help, unlike other banks, they can protect you, unlike other banks....etc.
Tosh, the personal subject pronoun "yo" is not downright forbidden. It's simply unnecessary in a whole lot of cases, but there are instances in which you need it for clarity and/or emphasis.
Pedro y yo llegamos a la iglesia y observamos como las aves volaban hacia el área posterior de la estructura.Tendría que ser un idiota para no verlas.
Should we have an additional "yo" somewhere in there? Where? why?
Then you learn they are somewhat optional.
Optional? Rubbish!! They are used for certain expressive purposed that normally are completely out of place.
I can help!
Yo puedo ayudar!
Florida is in USA. Spanish is a "second-class" language that many Americans look down upon, and many Spanish natives have a complex about it, because they don't think it is as good as English is. Being in a country where speaking English means being smart, educated, rich and influential, it is no wonder foreigners imitate the local speech, and eventually adopt it as a norm.
If you came to me and said that you found all those "yo" in a country where 100% of the people speak Spanish all the time, I would have no answer to give to you, but you are talking about USA!
Now, a possible alternative explanation is that you go and ask many people in the bank, and after getting no response, someone comes and says "¡Yo puedo ayudarte!", insinuating that, unlike the rest, he can actually help you. This, in any case, would not be very professional, and it could even be interpreted as an insult. I am more inclined to think that it is a Spanish "tinted" by the influence of the official language of the country you are in. No language remains totally isolated when its speakers have to constantly interact with people who speak another language on a daily basis, especially when the other language is the official one.
Pedro y yo llegamos a la iglesia y observamos como las aves volaban hacia el área posterior de la estructura.Tendría que ser un idiota para no verlas.
Should we have an additional "yo" somewhere in there? Where? why?
There is a why, actually, but instead of quoting a boring grammatical rule, just consider this sentence:
Pedro y.... llegamos a la iglesia....
Pedro and whom? The sentence is deliberately confusing without a pronoun. In these cases, the pronoun is absolutely compulsory... unless your intention is to get people completely confused about what you say.
I figured as much... that it was used for emphasis, but it didn't look like it was needed in the picture.
There was just a guy standing there in each picture.
Not a guy jumping up and down raising his hand. 
But thank you for the clarifications!!
Yep, yo is used for emphasis, in this case, Who can help? (You might be wondering?).
Well, I can help... You see this alot in these kinds of ads.
I see this all the time here in Colorado. I think it is just used to add emphasis.
I agree, tú, yo, él, ella, usted, they aren´t needed if the verb already shows who´s doing it (the indirect object). The handy thing about that is that if I then say
¿Dónde está el fuego?
and someone says
Yo lo tengo.
They are saying "I have it" (as opposed to it being in your pocket or under the table or stolen or wherever you thought it was), but in Spanish I think you don´t really need to say Pues YO no voy!!! as in Heidita´s comment because if you put in the "yo" unnecessarily then you may as well be putting in all that emphasis. You could be whispering it all "shhhhyo lo tengo" and it was still sound like I have it
So in chileno´s post when he says ¿Qué tú piensas, chico? I don´t feel like that´s so much an English link as it is just "What do YOU think, chico?" as opposed to "What do you think, chico?" It changes the feel.
And of course you already know those pronouns get used if the verb doesn´t mark clearly the indirect object.
Hey, Tosh,
The ads were probably written by someone using our
machine translators . . .
N
What happens is that in Florida is full of Cubans and they have somewhat their own Spanish, that without being totally wrong, they have "mimicked" English.
¿Qué tú piensas, chico? (What do you think?)
yo is used if your a beginner and you need subject pronouns. duh! 
Also in imperfect tense, personal subject is added because the 1st personal and 3rd personal conjugations are mostly the same.
