Informal Spanish on the Internet-
I think the OP's question is a good one to continue with a sensible, informative and interesting discussion about Spanish and the internet. According to stats done by those involved in the field of language, it is the second most used language on the web after English. IMO, this coincides logically with the stats that reveal the top five most spoken languages in the world today and Spanish is in the top five category.
A new level of informal speech has evolved and continues to evolve out from the various types of informal interaction in Spanish on the web such as chat room discussions, msn and yahoo messenger, email, text messaging, blogs, etc. The communication via these methods between two people or more is quick with short form usage of words, abbreviations, codes and where applicable just a number or a letter. The key aspect to remember is to think in Spanish and use Spanish phonetics in order to decipher what's being said. The OP's example of "bay" must be read using Spanish phonetics not English phonetics in order to comprehend.
On an individual level whether you choose to communicate on the internet using these codes or not you will for sure encounter this informal usage of the language. From a language perspective my primary concern is that it's another factor that prohibits those who already can't spell in Spanish to continue sink in the abyss of deteriorated spelling in their primary language. Those who already can't differentiate between /b/ and /v/, /z/, /c/ and /s/, eliminate the /h/ when it should be written will only exacerbate their own spelling difficulties. As well, I have observed that many youth in the USA and Canada of Latino descent who have not been academically exposed to Spanish spell Spanish words with English phonetics, which is the reverse of the OP's example. What does this create? IMO, a potential language disaster because of the impact it has on two key languages, English and Spanish. However, for those who have a more liberal and innovative point of view about communication will consider this as a potential "new" parlance used for communication on the web only aka a hybrid language.
My second concern is the mixture of the two widely spoken languages, English and Spanish. The mixture of two hierarchy languages usually only happens when they co-exist. The best example is Spanish in the USA which obviously is unique with invented words, anglicisms, hispanicized anglicisms, calques etc. as compared to Spanish spoken in Spanish-speaking countries. The internet is just another vehicle that encourages the mixture of two languages in informal speech that will definitely continue to have an impact on both languages however; the impact currently affects Spanish more than it affects English at this point. Sociolinguistics studies in Spanish reveal the impact it has on the Spanish language from a lexical and grammatical point of view.
In general, where you see this type of informal speech used, the idea is to relay a message quickly with as few words as possible. For example, text messaging only allows a limited number of characters therefore complete sentences don't apply. However, when text messaging style communication is used in formal written language along with incorrect spelling etc. there is a chronic problem from a language perspective which probably already existed but further compounded by internet style communication.
Just an fyi one should not confuse internet informal speech with colloquial speech. For example,
pa'que sepas, t? no sabes na' (colloquial speech) are not the same as
toynkasa (estoy en casa) which is internet jargon used in text messaging, chat room conversation etc. I sent text messages last week to a friend for the first time and it was a challenge. I did have to use short incomplete sentences to stay within the set character limits. It adds perspective to what you see happening with languages. I don't envision myself using the new found vocabulary in Spanish or English as I prefer to maintain some kind of standard. English examples such as B4, u, u 2, and Spanish ones
such as q (que). b.d. (buenos d?as), b.n. (buenas noches), c% (cien por ciento) etc. sometimes are even more difficult to understand as they are codes or shortened forms of words.
Here is a thread I posted in 2006 about Spanish and the internet. Surprisingly, the link to the article is still active.
http://www.dr1.com/forums/spanish-101/52803-diccionario-de-palabras-usadas-en-internet.html
-LDG.